1. Field of the Invention
The present invention pertains to the fabrication of anchors and other structures having variable-buoyancy. As described in more detail below, the structures fabricated according to the present invention may be utilized in any of a wide variety of different maritime applications.
2. Description of the Related Art
Conventionally, the most common type of anchor is a solid anchor, typically formed from concrete. However, other types of anchors also have been proposed and/or used. One such alternative is an anchor having an internal cavity that may be filled with air to make the anchor buoyant, thereby facilitating the raising of the anchor when desired. Examples of such variable-buoyancy anchors are described in U.S. Pat. No. 4,290,381, titled “Floating Marina” (the '381 patent); U.S. Pat. No. 6,106,198, titled “Method for Installation of Tension-Leg Platforms and Flexible Tendon”; and U.S. Pat. No. 6,170,424, titled “Production/Platform Mooring Configuration”; and European patent application EP 0 750 365, titled “Anchor for Underwater Electrodes”. The foregoing patents and patent applications are incorporated by reference herein as though set forth herein in full.
While such variable-buoyancy anchors can be quite useful, the fabrication of such anchors has been difficult. Typically, most anchor-fabricating techniques require the anchor to be constructed on land and then lifted and placed into the water using a crane. An alternative technique described in the '381 patent does not require the use of a crane, but still requires a substantial amount of effort. In that technique, an excavation is dug at least 25 feet from the shoreline and then a trench is dug from the water to that excavation. Not only does this technique require a significant amount of effort, but it may only be used in locations where there is adequate space for such an excavation and trench.